The manufacture of semiconductor devices on semiconductor or other substrates requires a multitude of separate processing operations carried out in separate manufacturing tools. Much of the semiconductor manufacturing process is an automated process. This includes the movement and transport of substrates within and throughout manufacturing tools. This also includes the loading and unloading operations associated with a particular piece of manufacturing equipment. The transfer of lots of wafers, i.e. substrates, and individual substrates throughout the fabrication area and to and from the individual manufacturing tools is also desirably an automated robotic operation. It is also desired to carry out cleaning operations of components of the semiconductor manufacturing tools using automated processes, for removing, manipulating and transporting the components.
The use of automated loading and unloading and transferring operations minimizes the number of times an individual must handle a semiconductor substrate, a cassette of semiconductor substrates or components of the manufacturing tools.
In some operations, it is still necessary to load and unload substrates and position components of manufacturing tools manually. In MOCVD (metal organic chemical vapor deposition) and many other operations, substrates are retained on discs that spin rapidly and the discs cannot be formed with any holes therethrough because the inlet and outlet gases are delivered to and exhausted from, the underside of the spinning disc. Since the spinning disc cannot have any holes extending therethrough, they do not include pinholes for receiving automatic substrate transfer holders with pins that are received in such holes. In many systems, the substrate fits snugly within the outer lips of the rotating disc, making it difficult to extract the substrate from the rotating disc. As such, the substrates undergoing MOCVD and many other similar processing operations, must be manually unloaded by hand. This is time-consuming and generates contamination.
Better methods are needed for transporting substrates that cannot be transported utilizing transfer plates with subjacent pins.